Nowadays, keys on electronic products are generally classified into Carbon keys (silicone keys) and DOME keys (metal dome keys). The Carbon keys are suitable for products having low requirements on the appearance such as electronic game machines and TV remote-controller. The DOME keys are suitable for products having high requirements on the appearance such as mobile phones and control keys for TVs.
Currently, common mobile phones usually adopt DOME key devices. As shown in FIG. 1, a DOME key device comprises a circuit board 110, a metal dome (not shown) and a key. The key comprises two electrodes, i.e., a fourth electrode 120 and a fifth electrode 130. When the metal dome is pressed down, the fourth electrode 120 and the fifth electrode 130 are electrically connected with each other to accomplish the key function of the mobile phone.
As there are different consumer groups in the market, different styles and types of mobile phones have been developed and, accordingly, different mainboards are used by the different types of mobile phones. However, some types of mobile phones have similar mainboards; e.g., a mainboard of a U10 type mobile phone is different from that of a U2 type mobile phone only in positions of some keys. If it is desired to produce the U10 type mobile phone by using the mainboard of the U2 type mobile phone, then use of two PCBs is usually needed, which increases the cost of the product and prolongs the duration of research and development. Therefore, mainboards of conventional mobile phones are incompatible, which brings inconvenience to the production.
Accordingly, a need still exists in the art to improve the design of the existing keys.